Preheat oven to 400 degrees F. Wash cucumbers. Cut the ends off the cucumbers; remove peel if it is tough or bitter. Slice the cucumbers lengthwise; use a spoon to remove any large seeds; cut into 1/4 inch slices. Place the sliced cucumbers in a colander; sprinkle with kosher salt and stir. Let stand for 25 minutes. Spread the slivered almonds on a baking sheet and bake with the rack in the top position, at 400 degrees F until lightly browned - about 5 minutes (use a timer to prevent overbrowning); remove from oven and cool. Slice grapes in half lengthwise and place in a large bowl. Add blueberries. Rinse the salt from the cucumber slices and turn out onto several paper towels. Place a paper towel over the top and press dry. Add cucumbers to the bowl with the other fresh ingredients. Drizzle the olive oil and vinegar over the salad; add the garlic and sodium-free seasoning to taste; toss. Sprinkle the toasted almonds over the top and serve.